Long-chain alkane 1, 2-disulfonic acids and salts thereof



United States Patent LONG-CHAIN ALKANE 1,2-DISULFONIC ACIDS AND SALTS THEREOF Herbert Sargent, San Anselmo, Calif., assignor to California Research Corporation, San Francisco, Calif., a corporation of Delaware No Drawing. Application March 20, 1953, Serial No. 343,790

Claims. (Cl. 260-513) This invention relates to a novel class of surfaceactive agents and, more particularly, to novel sulfonic acids and salts thereof having superior detergent properties.

Sulfonic acids and their salts have heretofore been employed as detergents. To date, however, these compounds as detergents leave much to be desired and constant efforts are being made to improve their more important characteristics such as cotton laundering detergency, foam stability, resistance to caking, and ability to withstand precipitation by hard water salts. Furthermore, many of the previously known surface-active agents are chemically unstable and tend to decompose on aging.

It is, therefore, an object of this invention to provide a new class of surface-active agents having improved detergent properties.

A further object of this invention is the provision of a novel process for the preparation of a new and improved class of surface-active agents.

Other objects of the invention will be apparent from the disclosure which follows.

In accomplishment of the above objects, I have discovered a novel class of surface-active agents which may be conveniently described as long-chain alkane 1,2-disulfonic acids and their alkali metal and alkaline earth metal salts.

The compounds of my invention are distinguished from conventional sulfonic acid detergents in possessing two sulfonic polar groups at the end of a non-polar long-chain aliphatic hydrocarbon. They are characterized by their high cotton laundering detergency, unusually stable foam, high surface-activity, resistance to caking in dry form, and their ability to withstand precipitation by hard water salts. Furthermore, they are of an unusually stable nature despite the adjacent sulfonic acid polar groups at one end of the hydrocarbon molecule.

In the description of the compounds of my invention, the term long-chain alkane is employed in its conventional sense and contemplates alkane groups of at least 7 carbon atoms. Preferred compounds contain from about 10 to 26 and, more desirably, from about 16 to 22 carbon atoms per molecule. Although branched-chain alkanes are suitable, moderately branched-chain compounds are more desirable, and straight-chain alkanes are preferred. As previously mentioned, the compounds of my invention include the alkali metal and alkaline earth metal salts of the long-chain alkane, 1,2-disulfonic acids. The sodium, potassium and lithium salts are illustrative of the alkali metal salts with the sodium salt constituting a preferred species of the invention. The term alkali metal salt, as herein employed, also includes the ammonium salt which is well known as the equivalent of the alkali metal salts. Illustrative of the alkaline earth metal salts are the calcium, barium, and magnesium salts of the long-chain alkane 1,2-disulfonic acid.

According to my invention the above compounds are prepared by halogenating a long-chain l-olefin at the double bond and reacting the dihalide thus obtained with an aqueous solution of an alkali metal or an alkaline earth "ice metal sulfite at about to 200 C. For present purposes, bromine is the preferred halogenating agent and sodium sulfite is the preferred sulfonating agent. The halogenation is preferably carried out at temperatures in the range of about -l0 C. to 25 C. The long-chain alkane 1,2-disulfonic acids are produced by acidifying the alkali metal sulfonate or alkaline earth metal sulfonate and extracting the disulfonic acids thus obtained with ether. The acids, in turn, may be neutralized with any alkali metal or alkaline earth metal base to produce a desired salt.

The following examples are submitted in further illustration of the invention. Unless otherwise specified, the proportions given are on a weight basis.

Example 1 448 g. of normal l-hexadecene was treated at 0 C. with chlorine gas until a gain in weight equivalent to about 167 g. occurred, corresponding to about 2.4 atoms of chlorine per molecule of hexadecane. 154 g. of chlorinated hexadecane, 500 ml. of water and 170 g. of sodium sulfite were heated with stirring at about 200 to 205 C. for 21 hours in a stainless steel autoclave. Upon cooling, the liquid contents of the autoclave separated into two phases, giving the n-hexadecane 1,2-disodium sulfonate in the form of a nearly colorless aqueous solution as the lower phase.

Example 2 An olefinic fraction boiling in the range from 164 to 186 C. at 5 mm. pressure and having an average of 20 carbon atoms per molecule was obtained by thermally cracking petroleum wax. This olefin was brominated at about 10 C. to 15 C. 217 g. of the dibromide thus obtained was reacted with g. of anhydrous sodium sulfite and 500 ml. of water at about 161 to 164 C. with stirring for 32 hours. The reaction mixture was allowed to cool and then boiled with 1 liter of ethanol and filtered hot. The filtrate was cooled to 60 C. and extracted with two 250 ml. portions of mixed hexanes boiling in the range of 60 C. to 70 C. The aqueous alcoholic phase was then evaporated on a steam plate. Near the end of the removal of the alcohol the concentrate separated into two phases, the upper one consisting mainly of alkane 1,2-

disodium sulfonate and the lower being an aqueous solu- Upon cool- Sulfur, percent 13.2 I 7 Example 3 An olefinic thermally cracked petroleum Wax mixture boiling in the range from 116 C. to 141 C. at 5 mm. pressure and having an average of 16 carbon atoms per molecule was brominated at 10 C. to 15 C. 193 g. of this bromide, 150 g. of anhydrous sodium sulfite and 500 ml. of water were heated with stirring at about C. for 5 2 hours, in a stainless steel autoclave. The contents were allowed to cool and were then boiled with 1 liter of ethanol and filtered hot. The filtrate was cooled to about 60 C. and extracted with two 250 ml. portions of mixed Patented Apr. 2, 1957.

Theoretical Found hexanes. The aqueous alcoholic phase was then evaporated to remove the alcohol. Near the end of the removal of the alcohol the aqueous concentrate separated into two phases: the u per phase consisting predominantly of alkane 1,2-disodium sulfonate, and the lower phase being a highly concentrated aqueous solution of sodium bromide and sodium sulfite. The mixture was cooled and the alkane l,2-disodium sulfonate precipitated. The precipitate was separated by filtration and the filter cake rinsed with 75 ml. of ice water to give I60 g. of mixed alkane 1,2-disodium sul'fonates having an average of 16 carbon atoms in the form of a tan, non tacky powder.

Example 4 A mixture of primarily normal l-olefins boiling in the raugefrom 90 C. to 208 C. at 5 mm. pressure containing from 14 to 22 carbon atoms and having an average molecular weight correspondingto about 18 carbon atoms was obtained by thermally cracking petroleum wax. This mixture was brominated at to 15 C. 126 g. of the dibromide thus formed, 150 g. of anhydrous sodium sulfite, and 500 ml. of water were heated with stirring at about 150 C. for 96 hours in a stainless steel autoclave. The contents of the autoclave were cooled and allowed to dry at room temperature to give a tacky material. This material was deoiled by mixing with two liters of mixed hexanes, followed by filtration. The filter cake was rinsed with additional mixed hexanes and then mixed with 500 ml. of water. This aqueous mixture was then heated to boiling and 1 liter of boiling ethanol was added and the mixture filtered while hot. The filter cake was reslurried with 500 ml. of boiling ethanol and refiltered. The aqueous alcoholic extracts were collected and evaporated to remove the alcohol. Near the end of the removal of the alcohol two phases were formed. The upper phase contained the alkane 1,2 -disodium sulfonate as in the previous examples. Upon cooling, the upper alkane disodium sulfonate phase crystallized. The resulting mixture was filtered and the filter cake washed with 75 ml. of ice water. The filter cake upon drying gave 137 g. of mixed alkane disodium sulfonates containing from 14 to 22 carbon atoms and having an average molecular weight corresponding to about 18 carbon atoms in the form of an almost colorless, non-tacky, free-flowing powder.

Example 5 15.5 g. (0.03 mole) of a 1,2-disodium sulfonate having an average of 22 carbon atomswas shaken with a mixture of 60 ml. concentrated hydrochloric acid, 50

ml. of Water and 200 ml. of ether. Upon standing the mixture separated into three phases: solid sodium chloride, aqueous hydrochloric acid, and an upper layer of ether containing the free sulfonic acids.

The ether layer obtained above was separated and divided into four equal portions. The first portion was evaporated to give the free disulfonic acid as a soft waxy substance. The second portion was neutralized with dilute aqueous sodium hydroxide (slightly more than the theoretical amount was required) and upon evaporation the disodium salt was obtained as a non-tacky tan solid. The third portion was neutralized with aqueous ammonia; upon evaporation the diammonium salt was obtained as a hard waxy solid. The fourth, and last,

portion was neutralized with a slurry of magnesium oxide in water; upon evaporation the magnesium salt was obtained as a waxy solid.

As a demonstration of their generally superior characteristics, the cotton laundering detergency of a representative compound of the novel long-chain alkane disulfonate's according to the present invention was compared with that of a long-chain alkane monosulfonate. The compositions tested contained 40% by weight of active and by" weight of sodium sulfate builder. On the basis of a soap index of for a well-known soap at a concentration of 0.4%, by weight in water, the following results were obtained:

Although the alkane disulfonate of the present invention was used in only one-half the concentration, it was found to have approximately five times the detergency of the alkane monosodium sulf'onate.

I claim:

1. Detergent material selected from the group consisting of long chain alkane 1,2-disulfonic acids, the alkali metal, and alkaline earth metal salts of said acids, said material having 16 to 22 carbon atoms in the molecule.

2. Alkali metal salts of long chain alkane 1,2-disulfonic acids having 16 to 22 carbon atoms in the molecule.

3. Long chain alkane 1,2-disodium sulfonate containing 16 to 22 carbon atoms in the molecule.

4. Normal octadecane 1,2-disodium sulfonate.

5. Surface-active materials selected from the groupconsisting of long-chain alkane 1,2-disulfonic acids, the alkali metal salts of said acids; and the alkaline earth metal salts of said acids, said surface-active materials having a carbon content of from an average of 16 to an average of 22 carbon atoms.

6. Surface-active materials as defined in claim 5, consisting of long-chain alkane 1,2-disodium sulfonates.

7. Surface-active materials as defined in claim 5, consisting of long-chain alkane 1,2-dipotassi'u'm sulfonates.

8. Surface-active materials as defined in claim 5, consisting of long-chain alkane 1,2-diammonium sulfonates.

9. Surface-active materials as defined in claim 5, con sisting of long-chain alkane magnesium sulfonates.

10. Surface-active materials as defined in claim 5, consisting of long-chain calcium sulfonates.

References Cited in the file of this patent UNITED STATES PATENTS 2,061,620 Downing et a1 Nov. 24, 1936 2,243,332 Simo et-al May 27, 1941 2,653,970 Fessler Sept. 29, 1953 OTHER REFERENCES Worstall: Amer. Chem. Jour., vol. 20 (1898), p. 673. Stone: J. Amer. Chem. Soc. 58, 488-9 (1936). 

5. SURFACE-ACTIVE MATERIALS SELECTED FROM THE GROUP CONSISTING OF LONG-CHAIN ALKANE 1,2-DISULFONIC ACIDS, THE ALKALI METAL SALTS OF SAID ACIDS, AND THE ALKALINE EARTH METAL SALTS OF SAID ACIDS, SAID SURFACE-ACTIVE MATERIALS HAVING A CARBON CONTENT OF FROM AN AVERAGE OF 16 TO AN AVERAGE OF 22 CARBON ATOMS. 